Affiliation: | aDepartment of Nuclear Engineering, Chosun University, 375 Seosuk-dong, Dong-gu, Gwangju 501-759, Republic of Korea bDepartment of Mechanical Design Engineering, Chonbuk National University, 664-14 1Ga Deokjin-dong, Jeonju, Jeonbuk 561-756, Republic of Korea |